/*
* DS1286 Real Time Clock interface for Linux
*
* Copyright (C) 1998, 1999, 2000 Ralf Baechle
*
* Based on code written by Paul Gortmaker.
*
* This driver allows use of the real time clock (built into nearly all
* computers) from user space. It exports the /dev/rtc interface supporting
* various ioctl() and also the /proc/rtc pseudo-file for status
* information.
*
* The ioctls can be used to set the interrupt behaviour and generation rate
* from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make
* use of these timer interrupts, be they interval or alarm based.
*
* The /dev/rtc interface will block on reads until an interrupt has been
* received. If a RTC interrupt has already happened, it will output an
* unsigned long and then block. The output value contains the interrupt
* status in the low byte and the number of interrupts since the last read
* in the remaining high bytes. The /dev/rtc interface can also be used with
* the select(2) call.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/ds1286.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/bcd.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#define DS1286_VERSION "1.0"
/*
* We sponge a minor off of the misc major. No need slurping
* up another valuable major dev number for this. If you add
* an ioctl, make sure you don't conflict with SPARC's RTC
* ioctls.
*/
static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait);
static ssize_t ds1286_read(struct file *file, char *buf,
size_t count, loff_t *ppos);
static int ds1286_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
static unsigned int ds1286_poll(struct file *file, poll_table *wait);
static void ds1286_get_alm_time (struct rtc_time *alm_tm);
static void ds1286_get_time(struct rtc_time *rtc_tm);
static int ds1286_set_time(struct rtc_time *rtc_tm);
static inline unsigned char ds1286_is_updating(void);
static DEFINE_SPINLOCK(ds1286_lock);
static int ds1286_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
/*
* Bits in rtc_status. (7 bits of room for future expansion)
*/
#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
#define RTC_TIMER_ON 0x02 /* missed irq timer active */
static unsigned char ds1286_status; /* bitmapped status byte. */
static unsigned char days_in_mo[] = {
0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/*
* Now all the various file operations that we export.
*/
static ssize_t ds1286_read(struct file *file, char *buf,
size_t count, loff_t *ppos)
{
return -EIO;
}
static int ds1286_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct rtc_time wtime;
switch (cmd) {
case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val |= RTC_TDM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_AIE_ON: /* Allow alarm interrupts. */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val &= ~RTC_TDM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val |= RTC_WAM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_WIE_ON: /* Allow watchdog interrupts. */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val &= ~RTC_WAM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_ALM_READ: /* Read the present alarm time */
{
/*
* This returns a struct rtc_time. Reading >= 0xc0
* means "don't care" or "match all". Only the tm_hour,
* tm_min, and tm_sec values are filled in.
*/
memset(&wtime, 0, sizeof(wtime));
ds1286_get_alm_time(&wtime);
break;
}
case RTC_ALM_SET: /* Store a time into the alarm */
{
/*
* This expects a struct rtc_time. Writing 0xff means
* "don't care" or "match all". Only the tm_hour,
* tm_min and tm_sec are used.
*/
unsigned char hrs, min, sec;
struct rtc_time alm_tm;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
sizeof(struct rtc_time)))
return -EFAULT;
hrs = alm_tm.tm_hour;
min = alm_tm.tm_min;
if (hrs >= 24)
hrs = 0xff;
if (min >= 60)
min = 0xff;
BIN_TO_BCD(sec);
BIN_TO_BCD(min);
BIN_TO_BCD(hrs);
spin_lock(&ds1286_lock);
rtc_write(hrs, RTC_HOURS_ALARM);
rtc_write(min, RTC_MINUTES_ALARM);
spin_unlock(&ds1286_lock);
return 0;
}
case RTC_RD_TIME: /* Read the time/date from RTC */
{
memset(&wtime, 0, sizeof(wtime));
ds1286_get_time(&wtime);
break;
}
case RTC_SET_TIME: /* Set the RTC */
{
struct rtc_time rtc_tm;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
sizeof(struct rtc_time)))
return -EFAULT;
return ds1286_set_time(&rtc_tm);
}
default:
return -EINVAL;
}
return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
}
/*
* We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean
* up things on a close.
*/
static int ds1286_open(struct inode *inode, struct file *file)
{
spin_lock_irq(&ds1286_lock);
if (ds1286_status & RTC_IS_OPEN)
goto out_busy;
ds1286_status |= RTC_IS_OPEN;
spin_unlock_irq(&ds1286_lock);
return 0;
out_busy:
spin_lock_irq(&ds1286_lock);
return -EBUSY;
}
static int ds1286_release(struct inode *inode, struct file *file)
{
ds1286_status &= ~RTC_IS_OPEN;
return 0;
}
static unsigned int ds1286_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &ds1286_wait, wait);
return 0;
}
/*
* The various file operations we support.
*/
static const struct file_operations ds1286_fops = {
.llseek = no_llseek,
.read = ds1286_read,
.poll = ds1286_poll,
.ioctl = ds1286_ioctl,
.open = ds1286_open,
.release = ds1286_release,
};
static struct miscdevice ds1286_dev=
{
.minor = RTC_MINOR,
.name = "rtc",
.fops = &ds1286_fops,
};
static int __init ds1286_init(void)
{
int err;
printk(KERN_INFO "DS1286 Real Time Clock Driver v%s\n", DS1286_VERSION);
err = misc_register(&ds1286_dev);
if (err)
goto out;
if (!create_proc_read_entry("driver/rtc", 0, 0, ds1286_read_proc, NULL)) {
err = -ENOMEM;
goto out_deregister;
}
return 0;
out_deregister:
misc_deregister(&ds1286_dev);
out:
return err;
}
static void __exit ds1286_exit(void)
{
remove_proc_entry("driver/rtc", NULL);
misc_deregister(&ds1286_dev);
}
static char *days[] = {
"***", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
/*
* Info exported via "/proc/rtc".
*/
static int ds1286_proc_output(char *buf)
{
char *p, *s;
struct rtc_time tm;
unsigned char hundredth, month, cmd, amode;
p = buf;
ds1286_get_time(&tm);
hundredth = rtc_read(RTC_HUNDREDTH_SECOND);
BCD_TO_BIN(hundredth);
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d.%02d\n"
"rtc_date\t: %04d-%02d-%02d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec, hundredth,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
/*
* We implicitly assume 24hr mode here. Alarm values >= 0xc0 will
* match any value for that particular field. Values that are
* greater than a valid time, but less than 0xc0 shouldn't appear.
*/
ds1286_get_alm_time(&tm);
p += sprintf(p, "alarm\t\t: %s ", days[tm.tm_wday]);
if (tm.tm_hour <= 24)
p += sprintf(p, "%02d:", tm.tm_hour);
else
p += sprintf(p, "**:");
if (tm.tm_min <= 59)
p += sprintf(p, "%02d\n", tm.tm_min);
else
p += sprintf(p, "**\n");
month = rtc_read(RTC_MONTH);
p += sprintf(p,
"oscillator\t: %s\n"
"square_wave\t: %s\n",
(month & RTC_EOSC) ? "disabled" : "enabled",
(month & RTC_ESQW) ? "disabled" : "enabled");
amode = ((rtc_read(RTC_MINUTES_ALARM) & 0x80) >> 5) |
((rtc_read(RTC_HOURS_ALARM) & 0x80) >> 6) |
((rtc_read(RTC_DAY_ALARM) & 0x80) >> 7);
if (amode == 7) s = "each minute";
else if (amode == 3) s = "minutes match";
else if (amode == 1) s = "hours and minutes match";
else if (amode == 0) s = "days, hours and minutes match";
else s = "invalid";
p += sprintf(p, "alarm_mode\t: %s\n", s);
cmd = rtc_read(RTC_CMD);
p += sprintf(p,
"alarm_enable\t: %s\n"
"wdog_alarm\t: %s\n"
"alarm_mask\t: %s\n"
"wdog_alarm_mask\t: %s\n"
"interrupt_mode\t: %s\n"
"INTB_mode\t: %s_active\n"
"interrupt_pins\t: %s\n",
(cmd & RTC_TDF) ? "yes" : "no",
(cmd & RTC_WAF) ? "yes" : "no",
(cmd & RTC_TDM) ? "disabled" : "enabled",
(cmd & RTC_WAM) ? "disabled" : "enabled",
(cmd & RTC_PU_LVL) ? "pulse" : "level",
(cmd & RTC_IBH_LO) ? "low" : "high",
(cmd & RTC_IPSW) ? "unswapped" : "swapped");
return p - buf;
}
static int ds1286_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = ds1286_proc_output (page);
if (len <= off+count) *eof = 1;
*start = page + off;
len -= off;
if (len>count)
len = count;
if (len<0)
len = 0;
return len;
}
/*
* Returns true if a clock update is in progress
*/
static inline unsigned char ds1286_is_updating(void)
{
return rtc_read(RTC_CMD) & RTC_TE;
}
static void ds1286_get_time(struct rtc_time *rtc_tm)
{
unsigned char save_control;
unsigned long flags;
unsigned long uip_watchdog = jiffies;
/*
* read RTC once any update in progress is done. The update
* can take just over 2ms. We wait 10 to 20ms. There is no need to
* to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
* If you need to know *exactly* when a second has started, enable
* periodic update complete interrupts, (via ioctl) and then
* immediately read /dev/rtc which will block until you get the IRQ.
* Once the read clears, read the RTC time (again via ioctl). Easy.
*/
if (ds1286_is_updating() != 0)
while (jiffies - uip_watchdog < 2*HZ/100)
barrier();
/*
* Only the values that we read from the RTC are set. We leave
* tm_wday, tm_yday and tm_isdst untouched. Even though the
* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
* by the RTC when initially set to a non-zero value.
*/
spin_lock_irqsave(&ds1286_lock, flags);
save_control = rtc_read(RTC_CMD);
rtc_write((save_control|RTC_TE), RTC_CMD);
rtc_tm->tm_sec = rtc_read(RTC_SECONDS);
rtc_tm->tm_min = rtc_read(RTC_MINUTES);
rtc_tm->tm_hour = rtc_read(RTC_HOURS) & 0x3f;
rtc_tm->tm_mday = rtc_read(RTC_DATE);
rtc_tm->tm_mon = rtc_read(RTC_MONTH) & 0x1f;
rtc_tm->tm_year = rtc_read(RTC_YEAR);
rtc_write(save_control, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
BCD_TO_BIN(rtc_tm->tm_sec);
BCD_TO_BIN(rtc_tm->tm_min);
BCD_TO_BIN(rtc_tm->tm_hour);
BCD_TO_BIN(rtc_tm->tm_mday);
BCD_TO_BIN(rtc_tm->tm_mon);
BCD_TO_BIN(rtc_tm->tm_year);
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
if (rtc_tm->tm_year < 45)
rtc_tm->tm_year += 30;
if ((rtc_tm->tm_year += 40) < 70)
rtc_tm->tm_year += 100;
rtc_tm->tm_mon--;
}
static int ds1286_set_time(struct rtc_time *rtc_tm)
{
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned char save_control;
unsigned int yrs;
unsigned long flags;
yrs = rtc_tm->tm_year + 1900;
mon = rtc_tm->tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm->tm_mday;
hrs = rtc_tm->tm_hour;
min = rtc_tm->tm_min;
sec = rtc_tm->tm_sec;
if (yrs < 1970)
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
if ((yrs -= 1940) > 255) /* They are unsigned */
return -EINVAL;
if (yrs >= 100)
yrs -= 100;
BIN_TO_BCD(sec);
BIN_TO_BCD(min);
BIN_TO_BCD(hrs);
BIN_TO_BCD(day);
BIN_TO_BCD(mon);
BIN_TO_BCD(yrs);
spin_lock_irqsave(&ds1286_lock, flags);
save_control = rtc_read(RTC_CMD);
rtc_write((save_control|RTC_TE), RTC_CMD);
rtc_write(yrs, RTC_YEAR);
rtc_write(mon, RTC_MONTH);
rtc_write(day, RTC_DATE);
rtc_write(hrs, RTC_HOURS);
rtc_write(min, RTC_MINUTES);
rtc_write(sec, RTC_SECONDS);
rtc_write(0, RTC_HUNDREDTH_SECOND);
rtc_write(save_control, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
static void ds1286_get_alm_time(struct rtc_time *alm_tm)
{
unsigned char cmd;
unsigned long flags;
/*
* Only the values that we read from the RTC are set. That
* means only tm_wday, tm_hour, tm_min.
*/
spin_lock_irqsave(&ds1286_lock, flags);
alm_tm->tm_min = rtc_read(RTC_MINUTES_ALARM) & 0x7f;
alm_tm->tm_hour = rtc_read(RTC_HOURS_ALARM) & 0x1f;
alm_tm->tm_wday = rtc_read(RTC_DAY_ALARM) & 0x07;
cmd = rtc_read(RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
BCD_TO_BIN(alm_tm->tm_min);
BCD_TO_BIN(alm_tm->tm_hour);
alm_tm->tm_sec = 0;
}
module_init(ds1286_init);
module_exit(ds1286_exit);
MODULE_AUTHOR("Ralf Baechle");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(RTC_MINOR);
